While there are many folk (often with dubious motivation) who claim that Renewable Energy Sources can never supply all a nations electricity needs, there is also a rather more sensible discussion on the role of nuclear power in the operation of our grids.

The thinking is that nuclear provides a robust, ‘firm’ (i.e. predictable and available) electricity supply that ensures that the baseload is covered. This is because renewables are intermittent.

Intermittency and capacity factors

Modern UK renewables perform far better than the long‑term fleet averages suggest: new offshore wind farms typically achieve 45–55% capacity factors, reflecting taller towers, larger rotors and steadier North Sea winds; new onshore wind sites reach around 30–40%, though the national average remains lower because many older turbines are still in the mix;  solar farms in the UK are roughly 11–12%, limited mainly by latitude rather than technology.

To add perspective firm generation, nuclear usually runs at 70–80%, shaped by long maintenance outages but high reliability when online, while gas CCGT stations operate at about 30–50% in practice, not because they cannot run harder but because they increasingly serve as mid‑merit and peaking plant in a renewables‑led system.

To address the intermittency issue the suggestion is that we need more nuclear in order to eliminate gas and so achieve a zero carbon emissions grid. It’s more than a suggestion, as literally billions of pounds are being invested in nuclear plants. Is this a wise investment?

Do we need nuclear power?

Let’s explore the topic in more detail. The following isn’t definitive, none of the team here are nuclear energy engineers, but we are well informed.

There is a credible case that, in the next 10–20 years, countries with strong renewable resources  are unlikely to need new grid‑connected nuclear.  Renewables + storage + demand flexibility are scaling faster, are cheaper, and are more predictable than nuclear can be deployed. Nuclear may still play a role in some regions, but it need not be a system necessity in the medium term.

Looking ahead

By 2040–2045, most grids can reach 80–95 percent decarbonisation using RES, storage, interconnection, and demand‑side management alone. 
Nuclear is only “needed” in systems that lack good renewable resources, have weak grids, or have political reasons to prefer it.

Renewable scaling is outpacing every forecast

Wind and solar are now adding >500 GW per year globally, and the IEA expects this to exceed 800 GW/year by 2030. 
That is equivalent to adding one Hinkley Point C every 2–3 days in energy terms.

– Solar module prices fell over 90 percent in 15 years. 
– Offshore wind is scaling into the 20–25 MW turbine era. 
– Build times are 1–3 years, not 10–15.

Renewables (RES) are now the default new generation source worldwide.

Storage is scaling even faster than RES

Battery storage is the fastest‑growing energy technology on the planet.

– Global grid‑scale storage capacity doubled in 2023. 
– Lithium‑iron‑phosphate (LFP) prices fell >50 percent in 2023 alone. 
– Multi‑day storage (iron‑air, sodium‑ion, flow batteries) is entering commercial deployment. 
– Pumped hydro is being expanded in Europe, China, and Australia.

By 2035, storage will be cheaper, more diverse (short, medium, long duration) and more widely deployed.

This directly reduces the need for nuclear as a “firm” resource.

Demand follows supply

Demand‑side management is the emerging grid management tool.
Flexibility in demand is becoming a major grid resource and has been successfully pointed, and is not being operationalised. In fact NESO announced a nation wide introduction of ‘turn up’ and ‘turm down’ events, building on the saver sessions etc. from Octopus Energy, SSE and Eon. The electricity demand increases that could stress the grid are associated with the very technologies that can be controlled in this way:
– EV smart charging 
– Heat pumps with thermal storage 
– Industrial load shifting 
– Data centre flexibility 
– Home batteries and V2G

By 2035, many grids will have 10–20% flexible demand, which dramatically reduces the need for slow‑ramping baseload like nuclear.

Nuclear cannot scale fast enough

Even if you want nuclear, the timelines are incompatible with 2035–2045 decarbonisation goals. They can’t be built fast enough to matter in the medium term, even with massive capital spend.

SMRs may help, but there are only two production SMRs in the world. They are in Russia…  SMRs are unlikely to play a major role where RES are an option.

Current nuclear plants:
– First concrete to operation: 10–15 years 
– Cost overruns: common 
– Workforce shortages: severe 
– Supply chain constraints: chronic 
– SMRs: effectively no commercial units operating yet; earliest realistic deployment is mid‑2030s, scaling in 2040s.

In contrast:
– A 1 GW solar farm can be built in 12–18 months 
– A 1 GW offshore wind farm in 3–5 years 
– A 1 GWh battery farm in 6–12 months

Nuclear simply cannot compete on deployment speed.

Economics

Nuclear is expensive. 3–5 times more expensive.

Levelised Cost of Electricity (LCOE) is a measure of the average cost to generate one megawatt‑hour of electricity over a power plant’s lifetime, including construction, operation, maintenance, and fuel, allowing direct comparison of technologies on a consistent €/MWh basis.

The Levelised Cost Of Electricity (LCOE) comparison is:

– Solar PV: €25–50/MWh 
– Onshore wind: €30–60/MWh 
– Offshore wind: €60–100/MWh 
– Grid batteries: €10–30/MWh for shifting 
– New nuclear: €120–250/MWh

This cost gap is widening, not narrowing.

UK scenario

A few facts and observations that underpin our prediction:
– Offshore wind pipeline: >100 GW 
– Nuclear pipeline: mostly theoretical 
– Storage: grid scale is doubling every 2-3 years, currently at ~100GWh (and another 6GWh in homes)
– Interconnectors: actively expanding 

The UK may want nuclear for political reasons, but it does not strictly need it.

Will we need grid‑connected nuclear in the next 10–20 years?

For most countries: no. 
For some countries: maybe.

Countries unlikely to need nuclear

• Much of Europe 
• UK 
• Denmark 
• Spain 
• Portugal 
• Australia 
• Chile 
• Most of Africa 
• Most of South America

Countries that may still want nuclear

• France (fleet replacement) 
• Finland (political support) 
• South Korea (industrial policy) 
• Japan (energy security) 
• China (all‑of‑the‑above strategy) 
• US (regional politics + existing fleet)

But even in these countries, nuclear is a policy choice, not a technical necessity.

In the medium term, RES + storage + demand flexibility will meet almost all new electricity needs in most regions. Nuclear is not required for grid stability or decarbonisation in that timeframe. Energy storage is very likely to have the capacity, longevity and cost-effectiveness to make nuclear a stranded asset. Unlike nuclear, the materials in batteries will be recyclable when they need replacing.

Nuclear may still be built for political, industrial, or strategic reasons, but not because the grid needs it.